[Trying to think of why this would not work, outside of a clearance issue, but wondering if I could use a quad tire on the ol PT. Next year will be tire replacement year.... and as I have 11 tires to replace, gonna need some serious cash to pull this off. Found some quad tires I liked the tread pattern on and was just thinking it through.]
I have an older PT-422 with the same body style as the newer PT-425.
I just put on a set of Kenda K502 4-ply off-road tires in size 23-10.5-12 designed for the small truck-like quads. They have a load rating in excess of 1340 pounds...very typical for a 4-ply tire which was standard on my machine. (Like the Carlisle turf tires and many of the tractor lug tires.)
I wanted the traction of the lugged tire, but need the turf-friendly behavior of the flatter treads. I think this is a great solution somewhere in the middle.
My property is a mix of woods, turf, and mud and is sloped at up to 25 degrees (much steeper than 25%) in places. These tires provide traction sufficient to climb the muddy hills in the steepest areas . I was amazed when I took it out the first time. It was raining and had made the hills too slick to walk on. The machine drove down, stopped and then backed up the hill with ease. Further, the tearing on the soil was minimal. I was impressed after slidding down these same hills in the dry on the turf tires.
As for load; the rating for the tires allows my weight, the full weight of the machine, and the full 800+ pounds of lift (ready to tip forward) to be safely carried by the front tires alone with 500 pounds to spare. Thus even on a side slope fully loaded, the downhill tire should safely stay in range. Further, these tires are designed for full load at up to 60 miles per hour, making the rating at slow speeds even a bit more conservative as it will not have the same heat generation.
If interested, they can be had on line for $144/pair with $25 delivery. My local shop mounted them for $25 for the 4. (Yes he is inexpensive) Thus, 4 new shoes for $375.
Rick
Still going strong after 2800 hours....but with new tires.